The field of the present invention is underwater lighting for pools and the like.
Swimming pools are subject in most jurisdictions to restrictive codes directed to the avoidance of electrical shock. Most typically, all conductive elements associated with the pool are to be grounded to a conductive net provided about the pool. This includes lighting fixtures. Additionally, powered fixtures are to be grounded to the electrical panel from which current is obtained for running the fixture such as a pool light.
A main pool light typically includes a conductive forming shell which is integrally associated with the structure of the pool and is electrically grounded to the pool grounding net. This conductive forming shell forms a niche in the side of the pool for receipt of a light housing. Such shells are typically displaced from an associated light housing with free water flow into the niche defined by the shell. The water admitted between the housing and the shell is used to cool the light.
Typical light housings are sealed with a lamp contained therein, a lens covering a front opening and a bezel about the lens which covers the periphery of the niche for aesthetic purposes and mounts the housing to the forming shell. The housings are typically conductive and have a ground wire extending as part of a cable through the forming shell and to the junction box. The conductive housing is also in electrical communication with the forming shell through the bezel and in turn with the pool grounding net.
Failure considerations in defining codes include the prospect of the lens being broken. Under such circumstances, electrical potential lines in the pool water are understood to form fields much like magnetic field lines. The metallic housing, bezel and forming shell all act to constrain the electric field and prevent shock to anyone nearby. The grounding through the net is further intended to prevent shock when someone comes in contact with another conductive element in the pool, such as a ladder or drain.